Lecture 25 Flashcards
As the adaptive immune sytem progresses to kill off an infection, how are the cells adapting?
More cells are specific to the pathogen (greater quantity)
Cells are more specialised (high affinity antibody or functionally polarised- greater quality)
Immunological memory definition
A small pool of specialised memory cells that develop during the adaptive immune response and persist in the absence of the antigen that originally induced them
Where do short lived plasma cells reside?
The lymph node or spleen
Where do long lived plasma cells reside?
In the bone marrow
What B cells are a source of long-lasting high-affinity class-switching antibody?
Long-lived plasma cells
How long are long-lived cells around for? What are they good at preventing?
Months. Good at preventing reinfection during an epidemic.
Where do memory B cells arise from?
Arise from the germinal center reaction
How are memory B cells different from other B cells?
They have inherited the genetic changes from the germinal center reactions
- they express high affinity antibody (already undergone somatic hypermutation)
- they have undergone antibody class switching
They also express higher levels of MHC II and co-stimulatory molecules than naive B cells
Where can memory B cells be found in the body?
Populate the spleen and lymph nodes and circulate through the blood
How often do memory B cells divide?
a. every week
b. once a year
c. when other memory B cells divide
d. very very slowly
d. very very slowly (if ever)
True or false: Memory B cells secrete antibody
False: they express surface Ig but do not secrete antibody
What do memory B cells do when they re-encounter antigen?
Quickly regenerate antibody producing plasma cells
True or false: memory T cells divide less frequently than naive T cells
False: They divide more frequently
memory t cell pool size is dictated by a balance of what?
A balance between cell proliferation and cell death
What cytokines are required to keep Memory T cells alive?
IL-7 and Il-15
True or false: Memory B and T cells require MHC activation to keep them alive
False: Only memory T cells require MHC activation to keep them alive
What are 4 reasons why memory T cells are better then naive T cells?
- they proliferate more than naice T cells and to lower antigen doses (aka they respond really quickly)
- they require less co-stimulation for activation than naive cells
- they produce cytokine faster and retain their polarised phenotype
- they may be strategically positioned in the tissue where the pathogen is likely to be encountered (e.g. wanting memory T cells against the flu in your lungs rather than your toes)
What are the two types of memory T cells?
Central memory and effector memory
Which of the following is true
a. both central memory and effector memory T cells express lymph-node homing molecules
b. neither central or effector express LNHM
c. only central memory
d. only effector memory
c. only central memory T cells express lymph-node homing molecules
True or false: central memory cells rapidly produce cytokine apon antigenic stimulation
False: effector memory T cells rapidly respond
Central memory T cells are FASTER/SLOWER than effector memory cells at producing cytokines upon antigenic stimulation
SLOWER